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Exploring Water's Life-Giving Properties: Chapter 3

Dive into the significance of H2O molecules, bonding, water transport in plants, and unique properties like surface tension, temperature moderation, and more. Learn about cohesion, adhesion, hydrogen bonding, acids, bases, solutions, the pH scale, buffers, and their roles in the world of water & life. Enjoy a comprehensive study of how these factors shape our understanding of water in its various forms!

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Exploring Water's Life-Giving Properties: Chapter 3

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  1. Water & Life Chapter 3

  2. H2O is why we are here • H2O molecules are polar • What does their polarity contribute to? • Each H2O molecule can form __ Hydrogen bonds?

  3. Cohesion & Adhesion • Caused by _________ ? • How does Cohesion differ from Adhesion? • When water travels upward in a straw, is that cohesion or adhesion? Why? • Diameter of straw: small or large? Why?

  4. Transpiration (Plants)

  5. Structure & Function in Water Transport • What structural feature of water enables it to be transported upward? • What structural feature of plant vessels enables water to be transported upward?

  6. Properties of Water • 1. High Surface Tension • 2. Temperature Moderation • 3. Evaporative Cooling • 4. Significant Solvency

  7. Surface Tension • Surface Tension – • Is surface tension a result of cohesion or adhesion? • Why?

  8. Temperature Moderation Temperature – measure of -- Water  Water can  Guess what type of bonding is responsible for high specific heat?

  9. Sea Breeze? (cranberry juice & …) • @ Day, • Air • Onshore breeze • @ Night • Hot air • Offshore breeze

  10. Evaporative Cooling • Water has high specific heat due to? • Responsible for cooling • Heat • Highest energy molecules • Vaporization involves the breaking of which bonds? • Conversely, when water vapor condenses, which bonds are formed?

  11. Hydrogen Bonding is cool

  12. Water • Which is more dense, liquid or solid H2O? • As temperature increases, what happens to density? • Why? • What does this mean for ocean stratification? • Which temperature (Celsius) is H2O the most dense?

  13. Properties of Water • 1. There are two cities, Davie and Pompano Beach, which will have a higher temperature during summer? • Why can we not use Weston instead of Davie? • 2. What bonds are broken during evaporative cooling? • 3. What force is responsible for cohesion? • 4. What force is responsible for adhesion?

  14. Like dissolves like… • Water is • Also dissolves • Polar substances = hydro • Water does not dissolve • Nonpolar substances = hydro • Hydro = water

  15. Remember… • Hydrophilic = ____ molecule • Will • Hydrophobic = _____ molecule • Will • What about ionic compounds?

  16. Acids & Bases • Hydrogen ion = _____ = _________ (H3O+) • Hydroxide ion (OH-) BUT only 1 in 554,000,000 H2O molecules is dissociated!!

  17. Definitions • There are 3, but we use the simplest, the Arrhenius definition • An acid_________________________________, it ______________________(ionizes) • A base________________________________, it ______________________________(ionizes) • HCl H+ + Cl- Acid or Base? • NaOH Na+ + OH- Acid or Base? • H2O  H+ + OH- Acid or Base?

  18. Acidic / Basic Solutions • @ 25⁰C, the product of [H+][OH-] = 10-14 • IF [H+] = [OH-], then [H+] = 10-7 • Called a ___________ as the amount of acid ___ base • IF [H+] > [OH-], then [H+] > 10-7 • Called an __________ as the amount of acid ___ base • Remember 10-6 OR 10-4___ 10-7 • IF [H+] < [OH-], then [H+] < 10-7 • Called a __________ as the amount of acid ___ base • Remember 10-8 OR 10-10___ 10-7

  19. pH Scale • pH = -log [H+] pOH = -log [OH-] • So for pH, just take the exponent of the [H+] • Guess what you should do for pOH? • If [H+] = 10-6, what is pH? • If [OH-] = 10-5, what is pOH? • AND just as [H+][OH-] = 10-14, pH + pOH = 14 • IF pH = 8, then pOH = ?? • IF pOH = 9, then pH = ??

  20. Buffer • … substances that _________________ • Mammals have a pH blood buffer, called the _______________ • H2CO3 HCO3- + H+ • What happens when acid enters? • What happens when base enters?

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